As our association is run by volunteers we have included this page to help with all the queries we get regarding information on Prader-Willi Syndrome for students. If you do not find what you are looking for here, just contact us through the email link at the bottom of the page. Student Information on Prader-Willi Syndrome FREQUENTLY ASKED QUESTIONS What is Prader-Willi syndrome (PWS)? PWS is a complex genetic disorder that typically causes low muscle tone, short stature, incomplete sexual development, cognitive disabilities, problem behaviors, and a chronic feeling of hunger that can lead to excessive eating and life-threatening obesity. What is the incidence of PWS? It is estimated to be about 1 in 20,000. Although considered a "rare" disorder, Prader-Willi syndrome is one of the most common conditions seen in genetics clinics and is the most common genetic cause of obesity that has been identified. PWS is found in people of both sexes and all races. How are people born with PWS? Most cases of PWS are attributed to a spontaneous genetic error that occurs at or near the time of conception for unknown reasons. This error results in either a deletion on the paternal chromosome 15 (approx. 70% of cases), uni parental disomy (UPD - approx. 25% of cases) where there are two chromosome 15's from the mother and none from the father, or an imprinting mutation (apporx. 5 % of cases). In a very small percentage of cases (2 percent or less), a genetic mutation that does not affect the parent is passed on to the child, and in these families more than one child may be affected. A PWS-like disorder can also be acquired after birth if the hypothalamus portion of the brain is damaged through injury or surgery. How is PWS diagnosed? Suspicion of the diagnosis is first assessed clinically, then confirmed by specialized genetic testing. Formal diagnostic criteria for the clinical recognition of PWS have been published (Holm et al, 1993), as have laboratory testing guidelines for PWS (ASHG, 1996). FURTHER INFORMATION You will find further information on this site related to specifics such as infants with PWS, a general guide, therapies & treatments and stories about our children and adults with PWS. Additionally, on the links page you will find PWS Associations worldwide - the USA, UK and New Zealand sites are particularly informative. Just use the navigation bar on the left. I NEED MORE INFORMATION If you find that a particular question you have is not answered above then you can email us at info@pws.org.au		• Frequently asked questions • Further information • Contact us